Apparatus for the adjustment of a form cylinder

ABSTRACT

In a multicolor offset printing machine, apparatus for circumferentially adjusting the form or perfecting cylinder for register printing, there is provided two pair of intermeshing gears. The first pair includes two helical gears coaxially arranged and axially shiftable relative to each other. One of these first gears carries a third gear engaging a pinion whose supporting rod is secured to the perfecting cylinder. The second pair of gears is jointly mounted to be rotatable about an axially shiftable axle which when so shifted causes the gears of the first pair to be angularly offset with respect to each other. This causes simultaneous displacement between the third gear means and the pinion which causes the perfecting cylinder to be correspondingly offset. The supporting rod of the pinion is also provided with means permitting it to be angularly adjusted thereby causing axial offset of the gears and consequent adjustment of the form cylinder with respect thereto.

[451 July 29, 1975 APPARATUS FOR THE ADJUSTMENT OF A FORM CYLINDERMiloslav Muselik, Hlavni, Czechoslovakia [75] Inventor:

[73] Assignee: Adamovske Strojirny Narodni podnik, Adamov,Czechoslovakia [22] Filed: Jan. 28, 1974 [21] Appl. No.: 436,910

[30] Foreign Application Priority Data Jan. 26, 1973 Czechoslovakia645-73 [52] US. Cl. 101/248; 74/440; 101/248;

104/247 [51] Int. Cl B4lf 13/24 [58] Field of Search l0l/248, 286

[56] References Cited UNITED STATES PATENTS 2,607,238 8/1952 English etal. 74/440 2,677,971 5/1954 Greenwood l0l/248 2,767,652 1(1/1956Dietrich et a1... 74/440 2,860,578 11/1958 Tregay l0l/248 3,065,69011/1962 Heller et al. 101/247 3,291,044 12/1966 Van Der Winden....l0l/247 3,496,865 2/1970 Fischer 101/248 Leuenberger 101/248 Weisgcrberl0 1 /248 Primary ExaminerEdgar S. Burr Assistant Examiner-WilliamPieprz Attorney, Agent, or FirmMurray Schaffer [57] ABSTRACT In amulticolor offset printing machine, apparatus for circumferentiallyadjusting the form or perfecting cylinder for register printing, thereis provided two pair of intermeshing gears. The first pair includes twohelical gears coaxially arranged and axially shiftable relative to eachother. One of these first gears carries a third gear engaging a pinionwhose supporting rod is secured to the perfecting cylinder. The secondpair of gears is jointly mounted to be rotatable about an axiallyshiftable axle which when so shifted causes the gears of the first pairto be angularly offset with respect to each other. This causessimultaneous displacement between the third gear means and the pinionwhich causes the perfecting cylinder to be correspondingly offset. Thesupporting rod of the pinion is also provided with means permitting itto be angularly adjusted thereby causing axial offset of the gears andconsequent adjustment of the form cylinder with respect thereto.

10 Claims, 7 Drawing Figures PATENTED JUL 2 9 1975 QN NW APPARATUS FORTHE ADJUSTMENT OF A FORM I CYLINDER BACKGROUND OF THE INVENTION Thepresent invention relates to apparatus for the circumferentialadjustment of the form or perfecting cylinder for register printingparticularly on multicolor offset printing machines.

In multicolor offset printing machines it is necessary to provide forthe continuous and accurate adjustment of the perfecting cylinder withthe printing cylinder so that quality register printing can be obtained.It is necessary that this adjustment be carried out when the printingmachine is in operation so that precise and accurate registration of thecolor can be obtained. It is also necessary to provide for suchadjustment when the machine is stopped so that the machine may be asaccurately set as possible prior to the institution of any printing.

One of the known devices for the circumferential adjustment of theperfecting cylinder for register printing includes the use of a pair ofgear wheels, one of which being a helical gear which is rotatablymounted on the side wall of the printing machine. The other gear of thepair of gear wheels is a spur gear which is coaxially attached to theperfecting cylinder. Engaging with the helical and spur gears is a pairof fixedly connected pinions which are mounted on a shiftablecountershaft. The end of the countershaft is provided with a thread. Acorresponding nut formed by a body which is affixed to the side wall ofthe printing machine engages the threaded portion. The countershaft hasthe function of a screw which is either directly or by means of anadditional transmission linkage connected with a control knob. Adisadvantage of the above device is that a spur gear connected to theperfecting cylinder must engage with the helical gear in order to obtainthe circumferential adjustment of the. perfecting cylinder. The spurgear results in the production of excessive vibration and noise whichhave a substantially negative effect upon proper register printing andto the perfecting of the coloration of the printing surfaces.

Another known device has a control mechanism arranged in the hollowshaft of the perfecting cylinder. The disadvantage of this type ofarrangement lies in the fact that the shaft of the perfecting cylindermust be hollow and consequently is considerably weaker and less rigidthan a solid cylinder shaft and consequently the cylinder shaft tends tobend and become deformed thus disturbing proper registration.

It is an object of the present invention to provide an arrangement forthe adjustment of the perfecting cylinder which overcomes thedisadvantages and defects of the prior known devices. I

It is a further object of the present invention to provide apparatus forthe circumferential adjustment of the perfecting cylinder either whenthe machine is stopped or during the continuous operation of the pressand while printing is being effected.

It is a further object of the present invention to provide apparatus forthe adjustment of the perfecting cylinder which is simple inconstruction yet which eliminates vibration and excessive noise andwhich main tains perfect registration once so adjusted during thecontinuous printing operation.

The above objects, other objects and numerous advantages will beapparent from the following disclosure of the present invention.

SUMMARY OF THE INVENTION in accordance with the present invention amulticolor offset printing machine having a printing cylinder and aperfecting cylinder is provided with apparatus for circumferentiallyadjusting the form cylinder for register printing. The apparatuscomprises a supporting shaft extending axially from one end of the formcylinder and about which a first gear means comprising an annularhelical main gear and an annular helical driven gear are arranged. Themain helical gear has a hub rotatable about the supporting shaft whilethe helical drive gear is coaxially arranged and rotatable with respectto the main gear. Second gear means is provided adjacent to the firstgear means and is adapted to mesh with and coact respectively with themain and the drive gears. The second gear means is rotatably mountedabout an axially movable axle so that the second gear means itself isreciprocally translatable with respect to the helical main and drivegears. A third gear means is secured to the hub of the main gearadjacent the end of the perfecting cylinder. A pinion engages the thirdgear means and is fixedly mounted on a rod extending into and securedwithin the perfecting cylinder. The helical drive gear is adapted to bedriven during the operation of the printing machine to effect conjointrotation of the perfecting cylinder with it and consequently therotation of the perfecting cylinder. The axial shifting of the axle onwhich the second gear means is rotatably mounted causes a relativeangular displacement of the helical main gear with respect to thehelical drive gear, consequently causing the third gear means toangularly displace the pinion and simultaneously to angularly displacethe perfecting cylinder relative to the helical main gear and thusrelative to the printing cylinder.

Preferably the axially movable axle holding the second set of gears ismanually operable. Thus the invention provides the advantage of enablingthe manual adjustment of the perfecting cylinder with respect to theprinting cylinder in a quick and easy manner during the continuedoperation of the printing machine. When the machine is stopped, a roughadjustment may be carried out by angularly adjusting the pinion to movethe helical gear means, in a reverse manner, so as to enable therelative adjustment between it and the perfecting cylinder to beeffected. Thereafter a more accurate registration of the perfectingcylinder may be achieved when the machine is put back into printingaction. As a result it is not necessary to stop the machine for eachminor adjustment of the perfecting cylinder. A

Preferably, the helical main gear and the helical drive gear each haveteeth inclined in an opposite direction to that of the other. As aresult the axial movement of the second gear system which intermesheswith the helical main and drive gears effects an angular offset which issignificantly larger than would be otherwise expected, consequentlypermitting a more accurate adjustment to be made.

Preferably, the third gear means comprises a gear wheel secured to thehelical main gear and a gear collar adjustably mounted on the gear wheelso as itself to be angularly offset with respect to it. Adjustment ofthis pair of gears enables the intermeshing with the pinion to be madewith a great deal of perfection eliminating backlash vibration and noisebetween them. Still further in accordance with the present invention thesupporting rod holding the pinion is retained in a holder mounted withinthe perfecting cylinder. The holder is provided with means by which theangular disposition of the rod may be adjustably fixed and with meansfor securing the rod in fixed position once this adjustment is made. Inthis manner the rough adjustment mentioned earlier can be easily made bymerely rotating the pinion support rod.

From the foregoing it will be seen that the present invention provides aconsiderable saving in make ready time necessary for arranging theprinting machine with the proper circumferential adjustment of theperfecting cylinder. Quicker and easier manipulation is obtained and amore accurate register printing is effected.

Full details of the present invention are given in the followingdescription of its preferred form and is shown in the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a front view of one of the latter ends of a form cylindershowing in partial section the apparatus of the present inventionarranged therewith,

FIG. 2 is a sectional view taken along line 2-2 of FIG. 3 showing inpartial end view a portion of the device of the present invention,

FIG. 3 is an enlarged sectional view of the apparatus as viewed in thedirection of line 3-3 of FIG. 2,

FIG. 4 is an enlarged plan view, partially in section, showing a portionof the perfecting cylinder and its adjusting pinion,

FIG. 5 is a partial sectional view taken along line 5-5 of FIG. 4,

FIG. 6 is a partial sectional plane taken along line 6-6 of FIG. 4, and

FIG. 7 is a continuation of the partial section of FIG. 1 showing themounting of the axially movable adjusting shaft of the laterallyopposite end of the machine frame, shown in FIG. 1.

DESCRIPTION OF THE PRESENT INVENTION As seen in FIG. 1 only a portion ofone of the lateral ends of a conventional multicolor offset press isshown. A form cylinder 4 is provided with a supporting shaft 3 extendingoutwardly along its central axis and journaled for sliding rotationwithin a cylindrical hub 38. The hub 38 is provided with a main gear,generally depicted by the numeral 1, formed by integrally casting ormachining between the ends of the hub 38 a radially extending disc 38a.The peripherally outer end of the disc 38a is stepped to provide anouter shoulder 38b and an inner shoulder 380 of lesser diameter. Theperipheral surface of the outer shoulder 38b is provided with a helicaltooth gear configuration. Mounted so as to be slidably rotatable aboutthe inner shoulder 380 is an annular drive gear 2 having an outerperipheral surface also provided with a helical tooth gearconfiguration, the direction of pitch or incline of which is opposite tothat of the helix of the main gear 1.

The disc 38a is situated to provide a small inner hub portion 38d onwhich is mounted a spur type gear wheel 14. The gear wheel 14 isprovided with an elongated base, forming a cylindrical shoulder 14a onwhich a collar gear 15 also of the spur type is rotatably mounted. Thegear wheel 14 and the collar 15 are secured, as seen in FIG. 2 to thehelical main gear 1 by a plurality of bolts 16 which have their endsthreaded in bores formed in the disc 38a. Each of the bolts passesthrough an arcuate (circular segment) slot 29 formed in the collar gear15 which thus allows the collar gear 15 to be rotatably adjusted withrespect to the gear 14.

The collar gear 15 is, in addition to the arcuate slots 29, providedwith a plurality of circular-segmented or arcuate grooves 30 formed onits inner face adjacent to the gear wheel 14. A similarly arcuate groove39 is formed on the facing surface of the gear wheel 14 so as to formwith the grooves 30 an arcuate box. A compression spring 17 is retainedin the boxes formed by the grooves 30 and 39, one half of the spring 17lying in the groove 30 while the other half lying in the groove 39. Thespring 17 thus resiliently biases the gear wheel 14 and the gear collar15 to one of their extreme angular relative positions against which biasthey may be subsequently adjusted by setting of the bolts 16. The headof the bolts 16 (FIG. 2) overlaps the edges of the slot 29 so that whenthe bolts are tightened, the gear wheel 14 and collar 15 are secured inrelatively fixed positions by being compressed against each other. Therange of rotary adjustment or turning of the collar gear 15 relative tothe gear wheel 14, and thus relative to the helical main gear 1 isdefined and limited by the extent of the slot 29.

The spur type gear wheel 14 and the gear collar 15 engage with a singleactuating pinion 18 fixed at the end of a rotatable shaft 19 mountedwithin a holder 21 (FIG. 3). The holder 21 is fixed within theperfecting cylinder by being mounted on the end face or side part of theperfecting cylinder 4 by at least a one bolt 24. The holder 21 is splitalong a planar slot 42 extending from one end to the other through thecylindrical bore adapted to receive the shaft 19. The rotatable shaft 19is provided with a threaded circular rack or screw gear 20 with which arotatable pinion 22, also journaled in the holder 21, meshes (FIG. 6).The pinion 22 has a bolt head so that it may be easily manipulated witha suitable tool. Rotation of the pinion 22 results in rotation of therod 19 on which the actuating pinion 18 is mounted. The rotatable rod 19is axially retained in the holder 21 by a securing screw 25 whose end isreceived in an annular slot 43 formed in the surface of the rod 19. Thusduring rotation of the rod 19 the rod may be prevented from axiallybeing removed from the holder 21. The rotatable rod 19 is clamped infixed rotative position after adjustment by a locking screw 23 whichextends transversely through the planar slot 42. The locking screw 23may be loosened and tightened as desired to clamp or free for rotatablerod and thus permit adjustment of the actuating pinion 18 into selectedposition.

Returning to FIG. 1, the outer end of the hub 38, which is longer thanits inner end is surrounded by a pair of spaced radial ball bearingstructures, generally defined by the numeral 6. The outer races of thebearing structures 6 are mounted in a cylindrical body or sleeve 5having a radially extending flange 5a which is securely fixed in theadjacent side wall 27 of the frame of the printing machine. In thismanner the perfecting cylinder 4 is supported at this end by the machineframe. The opposite end of the perfecting cylinder is supported in aspaced parallel side wall 40 seen in FIG. 7, in conventional manner. Theend of the shaft 3 is furthermore abutted by a ball type axial bearingheld by suitable retaining means fastened or keyed in the usual mannerto the hub 38 and is axially retained by a nut abutting against the wall27.

Arranged above the helical main gearand the helical drive gear forming afirst pair of gear means is an intermeshing and coacting pair of piniongears 7 and 8 forming a second pair of gear means. The pinion gear 7meshes with the helical drive gear 2 and is provided with an axiallyextending shoulder on which the second pinion gear 8 is securely fixedso as to mesh with the helical main gear 1. This arrangement of twopinion gears 7 and 8 is advantageous in that the gears may be moreeasily made and more easily arranged so that they mesh perfectly withthe respective helical drive gear 2 and main gear 1. The pinion gears 7and 8 are rotatably journaled about an elongated axle 9 seen in FIG. 1and in extension in FIG. 7..The shaft 9 is provided with a necked-downend portion about which a pair of radial ball bearings are arranged. Thepinion 7 is fixed to the outer race of the radial ball bearings so as tobe incapable of axial movement. The axial position of the pinion 7 isfurther secured by a spacer member 36 which fits over the outer end ofthe necked-down portion of the axle 9 and abutting the inner race of theouter ball bearing. This displaces the inner ball bearing against theshoulder forming the necked-down portion of the shaft 9. The spacer 36is secured to the end of the shaft 9 by a screw 36a thus firmly holdingthe pinion 7, and the pinion 8 mounted about it, against axialdisplacement in either direction.

The shaft 9 is, however, axially displaceable by slidably mounting thespacer 36 in a cylindrical bushing 10 which is fixed to the side wall 7of the'printing machine as seen in FIG. 1, and by mounting the centralportion of the shaft 9 in a tubular'sleeve 35 which has an armatelyenlarged outer cup-like portion 35a fixed at its edges to the wall 27 byscrews 3512. As seen in FIG. 7 the tubular spacer 35 extendstransversely across the printing machine, about the shaft 9 terminatingin a radial flange35c secured by bolts 35d to the opposite wall 40 ofthe printing machine. The shaft 9 extends through a hole in the wall 40and has a sleeve 11 surrounding it. The sleeve 11 is fixed against axialand rotational movement to the wall 40 and is provided with an internalscrew thread 11a. The shaft 9 is provided with a conforming thread 9a.The shaft 9 extends further outwardly beyond the wall 40 and has aknurled knob 12 secured to it by a set screw 37. An enlarged coveringmember 13 is secured by a second set screw 37a to the fixed sleeve 11.The cover member. 13 has an enlarged cup which surrounds the inner endof the knob 12. The peripheral wall of the cover 13 is provided with ahole in which a ball 28 is resiliently retained in conventional manner,to press againstthe surface of the knob 12. The knob 12 at this end isprovided with an annular groove, or if desired a plurality of discreetgrooves having a defined axial extent, uniformly spaced about thecircumference of the knob, as indicated by the numeral 41. Thus,manipulation of the knob 12 will rotate the shaft 9, causing the shaft 9to be axially displaced by the reaction of its thread 9a with thethreads 11a. The axial displacement causes the shaft 9 to reciprocateaxially with respect to the spaced walls 40 and 27 and thus with respectto the helical main drive gears shown in FIG. 1. The angular positionand axial extent of the displacement of the shaft 9 is limited anddefined by the position of the ball 28 in the annular groove or in aparticular oneof the discreet grooves all generally depicted by thenumeral 41.

Returning again to FIG. 1, the main gear 1 is provided with an annulardisc 31 having a right angle cross section; the vertical leg of which isfixed to the disc portion 38a while the horizontal leg portion extendstoward at slidable ring 33 mounted about the end of the perfectingcylinder 4 and in which an axial slot 34 extends annularly about itscentral axis. The horizontal leg of the disc 31 is provided with asuitable scale, having indicia of angular displacement, while theslidable ring 33 is provided with an indicating arrow 32 pointing to thescale 26.

Suitable gear means (not illustrated) is provided for engagement withthe drive gear 2 whereby the device as a whole may be driven. Thehelical drive gear 2 engages with the pinion 7 which rotates togetherwith its fixedly connected pinion 8 on the axially displaceable shaft 9.Thus conjoint rotation is obtained via the pinion 8 on the helical maingear 1. Under normal operating conditions the pinion- 18 is in clampedand fixedly locked position as is the third gear means comprising thespur gear 14 and the collar 15 thus rotation of the helical main gear 1will carry with it the perfecting cylinder 4, the shaft 3 rotating withthe hub 38.

The circumferential adjustment of the perfecting cylinder 4 foreffective register printing, is carried out during the printingoperation by turning the knob 12, seen in FIG. 7. As a result of therotation of the knob 12 the shaft 9 is axially displaced by beingscrewed into or out of the thread of the sleeve 11. The axialdisplacement of the shaft 9 carries with it the pinion 7 and the pinion8 as will be obvious from FIG. 1. Since the pinions 7 and 8 both haveteeth which mesh and coact with those of the helical drive gear 2 andthe main gear 1, they too are provided with teeth which are inclined ina direction opposite to the other. Thus, by the axial movement of thepinion 7 and the pinion 8, the main helical gear is angularly offset andturned relative to the drive gear 2, the drive gear 2 being slidablymounted on the disc 38a. The angular offset of the helical main gear 1carries with it the gear wheel 14 and the collar gear 15 which is firmlyfixed with the helical main gear 1 by the bolts 16. Since the gear wheel14 and the collar gear 15 engage the pinion 18 which is secured at theend of the rod 19, which in this case still remains firmly clamped tothe holder 21, the perfecting cylinder 4 is also angularly offset andthus also circumferentially adjusted for register printing, with respectto the printing cylinder. The helical drive gear 2, due to the fact thatits teeth are inclined in an opposite direction to the teeth of thehelical main gear 1, is turned in an opposite direction from that of thehelical main gear 1. By thus turning the helical gears in oppositedirections, a larger range of circumferential adjustment of theperfecting cylinder is made possible by very small axial displacementsof the shaft 9.

i The circumferential adjustment of the perfecting cylinder with respectto the printing cylinder, for register printing, while the printingmachine is stopped is carried out in the following manner: The lockingscrew 23 (FIG. 5) by which the rotatable rod 19 is clamped in fixedposition is loosened, thus permitting the screw pinion 22 to be rotated.On rotation of the screw pinion 22 the screw gear 20 formed on the rod19 allows the rod 19 to be pivoted about its central axis. In thismanner the actuating pinion 18 is itself turned and since it engageswith the pair of gears formed by the wheel gear 14 and the collar gear15, which gears are in fixed position due to the fact that they aresecurely fixed to the helical main'gear l which because the machine isin stopped condition, remains fixed. Thus the rotation of the pinion 18has a reverse action causing angular offset of the perfecting cylinder 4in a direction opposite to the direction of the turning of the mainhelical gear 1 and in a direction opposite to the turning of the helicaldrive gear 2, since both remain fixed. Once this angular adjustment ismade the rod 19 can again be clamped into its fixed position bymanipulation of the bolt 23.

The extent and value of the angular offset of the perfecting cylindercan be registered and controlled on the scale 26.

From the foregoing, it will be seen that the adjustment of theperfecting cylinder is obtained by the employment of a first pair ofcoaxially and relatively rotatable gears (l and 2) which are angularlyoffset and movable by a second pair of gears (7 and 8). One of theangularly adjustable gears is provided with a third gear means whichengages a pinion normally fixed in the perfecting cylinder so that uponits axial offset the third gear will cause corresponding angularadjustment of the perfecting cylinder. The apparatus is relativelysimple to coaxially and relatively angularly adjustable gears arecapable of a wide range of adjustment and preferably have helical gearfaces extending in opposite directions with respect to each other sothat this wide range of adjustments can be obtained. The second set ofgears meshing with the angularly adjustable gears are preferablyangularly offset which translated to the helical gear structure permitsan angular adjustment. The third gear means is comprised of a pair ofgears which themselves are angularly adjustable with respect to eachother and provided with resilient biasing means in which mannervibration and backlash characteristics can be easily avoided.

Various modifications and changes have been suggested in the disclosure,others will be apparent to those skilled in the art. It is thereforeintended that the present disclosure be taken as illustrative only ofthe present invention and not limiting of its scope in any manner.

What is claimed is:

1. In a multicolor offset printing machine having a printing cylinderand a perfecting cylinder, apparatus for circumferentially adjusting theperfecting cylinder for register printing comprising a supporting shaftextending axially from one end of the perfecting cylinder, first gearmeans comprising an annular helical main gear having a hub rotatablyarranged about said supporting shaft and an annular helical drive gearcoaxially mounted on a first shoulder of said hub and rotatable withrespect to said main gear, second gear means adapted to mesh with andcoact respectively with said main and drive gears, said second gearmeans being rotatably mounted about an axially movable axle, third gearmeans secured to said main gear on a second shoulder thereof adjacentthe end of the perfecting cylinder, a pinion engaging said third gearmeans and fixedly mounted on a rod extending into the end of saidperfecting cylinder and secured thereto, said helical drive gear beingadapted to be driven during operation of said printing machine to effectconjoint rotation of said helical main gear and said perfectingcylinder. whereby axial shifting of said axle would cause relativeangular displacement of said helical main gear and said helical drivegear consequently causing said third gear means to angularly displacesaid pinion causing said rod to angularly displace said perfectingcylinder relative to the helical main gear.

'2. The apparatus according to claim 1 wherein the helical main gear hasteeth inclined in an opposite direction to the' teeth of the helicaldrive gear.

3. The apparatus according to claim 2 wherein said second gear meanscomprise a pair of gears each having helical teeth conforming to saidmain gear and drive gears respectively.

4. The apparatus according to claim 1 wherein said pinion rod isretained in a holder mounted within said cylinder, said holder beingprovided with means for adjustably fixing the angular position of saidpinion rod about its longitudinal axis, wherein the relative position ofthe perfecting cylinder and the main gear are angularly adjustable.

5. The apparatus according to claim 1 wherein the third gear meanscomprises a spur gear secured to said helical main gear and a gearcollar adjustably mounted on a shoulder of said gear wheel to beangularly adjustable with respect thereto.

6. The apparatus according to claim 5 wherein the gear collar isprovided with a plurality of arcuate slots, screw means extendingthrough said arcuate slots and through said spur gear to be threadedlyretained in said helical main gear.

7. The apparatus according to claim 6 in which the facing surfaces ofsaid spur gear wheel and said spur gear collar is provided with aplurality of paired arcuate grooves, a spring located in each pair ofgrooves resiliently biasing said gear collar and spur gear wheel againstangular relative rotation.

8. The apparatus according to claim 4 including means for clamping saidpinion rod in said holder in fixed adjusted position.

9. The apparatus according to claim 1 including a disc fixed on thehelical main gear, said disc being provided with an axial leg extendinginto a circular slot formed in a slide ring mounted over the end of saidperfecting cylinder, said disc being provided with a scale and said ringbeing provided with an indicator marking located opposite to said scale.

10. The apparatus according to claim 1 wherein the means for axiallymoving said axle comprising a sleeve having an internal threaded boresurrounding said axle, said axle being formed with a conforming threadedsurface, and means for rotating said axle whereby the interaction ofsaid threaded surfaces causes axial displacement of said axle.

1. In a multicolor offset printing machine having a printing cylinderand a perfecting cylinder, apparatus for circumferentially adjusting theperfecting cylinder for register printing comprising a supporting shaftextending axially from one end of the perfecting cylinder, first gearmeans comprising an annular helical main gear having a hub rotatablyarranged about said supporting shaft and an annular helical drive gearcoaxially mounted on a first shoulder of said hub and rotatable withrespect to said main gear, second gear means adapted to mesh with andcoact respectively with said main and drive gears, said second gearmeans being rotatably mounted about an axially movable axle, third gearmeans secured to said main gear on a second shoulder thereof adjacentthe end of the perfecting cylinder, a pinion engaging said third gearmeans and fixedly mounted on a rod extending into the end of saidperfecting cylinder and secured thereto, said helical drive gear beingadapted to be driven during operation of said printing machine to effectconjoint rotation of said helical main gear and said perfectingcylinder, whereby axial shifting of said axle would cause relativeangular displacement of said helical main gear and said helical drivegear consequently causing said third gear means to angularly displacesaid pinion causing said rod to angularly displace said perfectingcylinder relative to the helical main gear.
 2. The apparatus accordingto claim 1 wherein the helical main gear has teeth inclined in anopposite direction to the teeth of the helical drive gear.
 3. Theapparatus according to claim 2 wherein said second gear means comprise apair of gears each having helical teeth conforming to said main gear anddrive gears respectively.
 4. The apparatus according to claim 1 whereinsaid pinion rod is retained in a holder mounted within said cylinder,said holder being provided with means for adjustably fixing the angularposition of said pinion rod about its longitudinal axis, wherein therelative position of the perfecting cylinder and the main gear areangularly adjustable.
 5. The apparatus according to claim 1 wherein thethird gear means comprises a spur gear secured to said helical main gearand a gear collar adjustably mounted on a shoulder of said gear wheel tobe angularly adjustable with respect thereto.
 6. The apparatus accordingto claim 5 wherein the gear collar is provided with a plurality ofarcuate slots, screw means extending through said arcuate slots andthrough said spur gear to be threadedly retained in said helical maingear.
 7. The apparatus according to claim 6 in which the facing surfacesof said spur gear wheel and said spur gear collar is provided with aplurality of paired arcuate grooves, a spring located in each pair ofgrooves resiliently biasing said gear collar and spur gear wheel againstangular relative rotation.
 8. The apparatus according to claim 4including means for Clamping said pinion rod in said holder in fixedadjusted position.
 9. The apparatus according to claim 1 including adisc fixed on the helical main gear, said disc being provided with anaxial leg extending into a circular slot formed in a slide ring mountedover the end of said perfecting cylinder, said disc being provided witha scale and said ring being provided with an indicator marking locatedopposite to said scale.
 10. The apparatus according to claim 1 whereinthe means for axially moving said axle comprising a sleeve having aninternal threaded bore surrounding said axle, said axle being formedwith a conforming threaded surface, and means for rotating said axlewhereby the interaction of said threaded surfaces causes axialdisplacement of said axle.